The present invention relates to equipment for changing, weakening or destroying biological structures in vivo and in vitro by means of a magnetic gradient field.
Magnetism and magnetically responsible particles have been used for a long time in various biochemical and medical applications. When paramagnetic materials are exposed to an externally alternating homogeneous magnetic field, heat is generated due to hysteresis. This generation of heat, in particular in combination with superparamagnetic nanoparticles, is used in cancer therapy and is then referred to as magnetic fluid hyperthermia (1). A cancer cell normally has a higher temperature than a healthy cell and therefore does not tolerate as high a temperature rise as a healthy cell. Thus, the cancer cells can be selectively destroyed or weakened without affecting the host organism. An alternative method is that the composition of the superparamagnetic particles is of such type that cancer cells are made to take in said particles into the cell, whereby the temperature is raised more efficiently in the cancer cell without any considerable heat loss to the environment. This type of therapy has been found to be promising, which is described, inter alia, in the patent literature (2, 3, 4, 5), even if there is no clinically approved magnetic equipment for this purpose for the time being.
A cell membrane is, inter alia, composed of lipids and fatty acids, which both have poor thermal conductivity, which makes it difficult to fight the target cell efficiently with only extracellular heat generated by hysteresis.
According to the present invention, a device is provided which solves the above-mentioned problems. Thus, a device is provided for increasing the thermal and/or kinetic energy of magnetically responsible particles, said device containing at least two magnetic field generating means, of which at least one is a coil, between which means an alternating magnetic gradient field can be generated in a spatially defined area, into which spatially defined area human or animal tissue can be introduced, said alternating magnetic gradient field causing an increase of the thermal and/or kinetic energy of magnetically responsible particles which have been added to said tissue, the increased thermal and/or kinetic energy of the magnetically responsible particles selectively reducing, deactivating or destroying endogenous or exogenous biological structures in said tissue.
In one embodiment of the invention, one of the magnetic field generating means is a permanent magnet.
In another embodiment of the invention, the device contains at least two coils and these coils are fed with alternating currents having different frequencies and/or amplitudes and/or phases, or alternatively said coils are fed with either the positive or the negative part of the fed alternating current.
Furthermore, the device can suitably be equipped with a thermostat for careful temperature control of said tissue and/or with variable time setting for careful control of the time during which said tissue is exposed to the alternating magnetic gradient field.
In one embodiment of the device, the alternating magnetic gradient field alternates with frequencies of up to 30 MHz and the field strength inside said coils amounts to at least 10 mT.
The tissue which is to be treated can be a body part or an inner organ or blood, which are returned to the host organism after completed exposure to the alternating magnetic gradient field.
The magnetically responsible particles suitably comprise a core of a metal oxide and a coating containing antibodies or parts thereof and have a size of 0.1-300 nm.
The magnetically responsible particles have been added to the host organism before the exposure of its tissue to the alternating magnetic gradient field, or alternatively after the tissue has been temporarily removed from the host organism.
The endogenous or exogenous biological structures consist, for instance, of mammal cells, malignant cells, plant cells, nerve cells, bacteria, viruses, cellular organelles, cell membranes, cell walls, liposomes, proteins, protozoa, parasites, peptides, drugs, toxins, organic compounds, inorganic compounds, or combinations thereof.
According to one aspect, the device is intended for in vivo or in vitro treatment of tumour diseases, endocrine disorders or infectious diseases.